Paging systems establish a one way communication channel providing information, e.g., telephone numbers or messages, to remote paging devices travelling within a reception area. An acknowledge signal originating from the paging device improves the paging system. For example, receiving an acknowledge-back signal benefits the paging system in verifying a given message transmitted via radio signal successfully arrived at the intended paging device.
Paging systems incorporating acknowledge-back features generally require extensive and complex implementation, i.e., elaborate protocol modification and sophisticated additional radio signal circuitry. For example, U.S. Pat. No. 5,260,700, issued Nov. 9, 1993 proposes enhanced throughput in simulcast communication systems by use of a selective call receiver system including a plurality of base sites capable of simultaneous operation. U.S. Pat. No. 5,162,790 issued Nov. 10, 1992 shows a multiple transmitter paging system including a central station having a plurality of acknowledge-back receivers, each operating on separate individual channels whereby a plurality of remote stations, each with a acknowledge-back receiver, selectively receives acknowledge-back responses on each of the individual channels. U.S. Pat. No. 5,142,279 issued Aug. 25, 1992 shows an acknowledge-back paging system having the capability of matching variable length data messages to pager addresses by selecting an order of transmission for variable length messages. U.S. Pat. No. 5,124,697 shows an acknowledge-back pager method for acknowledging the reception of an address signal by transmitting acknowledge signals determined at least in part by the received address signals positioned in a group of address signals to avoid simultaneous transmission of acknowledge signals. U.S. Pat. No. 4,940,963 issued Jul. 10, 1990 shows a paging system with acknowledge-back capability including immediate indication of message receipt to the paging system caller when a pager immediately acknowledges a paging message, and immediate indication of failure to deliver to the paging system caller when the pager fails to immediately acknowledge a paging message. U.S. Pat. No. 4,825,193 issued Apr. 25, 1989 shows an acknowledge-back pager system wherein a group of acknowledge-back pagers acknowledge simultaneously, but on different frequencies allocated dynamically to pagers in the group.
Some acknowledge-back pager systems suffer for excess complexity or significant modification to broadcast protocol otherwise used. Introducing additional complex radio signal circuitry or modification to paging system broadcast protocol is reflected in increased cost of acknowledge-back features to the users of the paging system.
It is desirable to provide an acknowledge-back capability in a paging device without incurring the substantial burden in expense and additional complex equipment typically required when incorporating broadcast of an acknowledge signal from a paging device.